Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[sfrench/cifs-2.6.git] / include / linux / trace_events.h

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 2bcb4dc6df1a38baf68282abc9505d62a9d8f1e2..84014ecfa67ff284fc6b657e565e57ea12d9c89e 100644 (file)
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -272,14 +272,37 @@ struct trace_event_call {
 #ifdef CONFIG_PERF_EVENTS
        int                             perf_refcount;
        struct hlist_head __percpu      *perf_events;
-       struct bpf_prog                 *prog;
-       struct perf_event               *bpf_prog_owner;
+       struct bpf_prog_array __rcu     *prog_array;
 
        int     (*perf_perm)(struct trace_event_call *,
                             struct perf_event *);
 #endif
 };
 
+#ifdef CONFIG_PERF_EVENTS
+static inline bool bpf_prog_array_valid(struct trace_event_call *call)
+{
+       /*
+        * This inline function checks whether call->prog_array
+        * is valid or not. The function is called in various places,
+        * outside rcu_read_lock/unlock, as a heuristic to speed up execution.
+        *
+        * If this function returns true, and later call->prog_array
+        * becomes false inside rcu_read_lock/unlock region,
+        * we bail out then. If this function return false,
+        * there is a risk that we might miss a few events if the checking
+        * were delayed until inside rcu_read_lock/unlock region and
+        * call->prog_array happened to become non-NULL then.
+        *
+        * Here, READ_ONCE() is used instead of rcu_access_pointer().
+        * rcu_access_pointer() requires the actual definition of
+        * "struct bpf_prog_array" while READ_ONCE() only needs
+        * a declaration of the same type.
+        */
+       return !!READ_ONCE(call->prog_array);
+}
+#endif
+
 static inline const char *
 trace_event_name(struct trace_event_call *call)
 {
@@ -436,12 +459,23 @@ trace_trigger_soft_disabled(struct trace_event_file *file)
 }
 
 #ifdef CONFIG_BPF_EVENTS
-unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx);
+unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx);
+int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog);
+void perf_event_detach_bpf_prog(struct perf_event *event);
 #else
-static inline unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
+static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
 {
        return 1;
 }
+
+static inline int
+perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
+{
+       return -EOPNOTSUPP;
+}
+
+static inline void perf_event_detach_bpf_prog(struct perf_event *event) { }
+
 #endif
 
 enum {
@@ -512,6 +546,7 @@ perf_trace_buf_submit(void *raw_data, int size, int rctx, u16 type,
 {
        perf_tp_event(type, count, raw_data, size, regs, head, rctx, task, event);
 }
+
 #endif
 
 #endif /* _LINUX_TRACE_EVENT_H */